Wavefront sensor, and lens meter and active optical reflecting telescope using the same

ABSTRACT

A wavefront sensor includes a plurality of lenses disposed in the same plane, and an area sensor that receives a bundle of rays of light collected through each of the lenses as a luminous point. Each of the lenses comprises a plurality of concentric areas with different focal lengths, and the area sensor is located substantially halfway between a first position in which a plane wave forms an image after passing through one of the concentric areas with a minimum focal length, and a second position in which the plane wave forms an image after passing through another area with a maximum focal length. With the wavefront sensor thus arranged, the measurement can be always achieved with high accuracy without involving noticeable blurring of luminous points on the area sensor regardless of the wavefront shape of a light beam incident to the lenses.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a wavefront sensor for measuringwavefront shape of a light beam, and a lens meter and an active opticalreflecting telescope using the wavefront sensor.

[0003] 2. Description of Related Art

[0004] Conventionally, a Hartmann wavefront sensor is known as awavefront sensor for measuring wavefront shape of a light beam. TheHartmann wavefront sensor includes a plate member called the Hartmannplate having multiple small openings regularly formed therein at aconstant interval, and an area sensor disposed parallel to the Hartmannplate. A light beam is radiated onto the Hartmann plate from theopposite side of the area sensor. The incident light beam forms a thinpencil or bundle of rays of light as it passes through the openings andcreates multiple luminous points on the area sensor according to thenumber of openings.

[0005] When the incident light beam is a plane wave, the intervalbetween the openings in the Hartmann plate and the interval between theluminous points on the area sensor are equal. Even when the interval ofthe openings and the interval of the luminous points are not equal, thedirection of light of the transmitted rays can be calculated from theposition of the luminous points on the area sensor, because the distancebetween the Hartmann plate and the area sensor, and the position of theopenings in the Hartmann plate are known. Because this direction isequal to a direction normal to the wave plane of incident light beam,wavefront shape of the incident light beam can be measured based onmultiple directions of the light.

[0006] On the other hand, in order to improve the S/N ratio, eachopening of the Hartmann plate is usually equipped with a single focuslens of the same specification, and the area sensor is dived on thefocal point of each lens.

[0007] The conventional wavefront sensor has a problem however that whenthe incident light beam is a plane wave, the S/N ratio can besufficiently improved by using a single focus lens and an area sensorlocated at the focal point of the single focus lens, however, if theincident light beam is not a plane wave, the luminous point on the areasensor becomes blurred and the S/N ratio decreases significantly.

[0008] As shown in FIG. 12(a), when a light beam P incident to a lens 2on the Hartmann plate 1 is a plane wave, light through the lens 2 iscollected at one point on an area sensor 3 and creates a luminous pointQ1. The luminous point Q1 has a luminous energy distribution indicatedby the solid line shown in FIG. 13. However, as shown in FIGS. 12(b) and12(c), when the incident light beam P is either divergent light orconvergent light, light transmitted through the lens 2 does not convergeon the area sensor 3 and creates a rather large-size luminous point Q2or Q3 on the area sensor 3. These luminous points Q2 and Q3 have aluminous energy distribution indicated by the broken line shown in FIG.13 and thus they are significantly blurred due to the absence of a clearluminous energy difference from the surroundings as demonstrated by theluminous point Q1. Therefore, when the luminous energy received by thearea sensor 3 decreases due to the presence of dust or scars on thelenses, it easily affects the luminous points Q2 and Q3, and in theworst case, these points cannot be recognized as a luminous point.

[0009] In addition, since the periphery of the blurred luminous point isunclear and extends outwardly far from the enter of the luminous point,the adjacent luminous points on the area sensor 3 may touch or overlapeach other. To avoid this, it is necessary either to shorten thedistance between the Hartmann plate 1 and the area sensor 3, or toenlarge the interval of the openings in the Hartmann plate 1. However,in the former case, for an incident light other than the plane wave, thedisplacement of the luminous point becomes small, lowering thesensitivity to the displacement. In the latter case, the density of theluminous point becomes small, decreasing the measurement point. Thus,the accuracy of the measurement of wavefront shape is deteriorated inboth cases.

[0010] Especially, when measuring a wavefront greatly distorted from aflat plane, such as a light beam transmitted through a lens, theabove-mentioned problems cannot be ignored, and it is absolutelynecessary to avoid remarkable blurring of the luminous points so as toimprove measurement accuracy.

SUMMARY OF THE INVENTION

[0011] With the foregoing in view, it is an object of the presentinvention to provide a wavefront sensor, which is capable of achieving ameasurement with high accuracy by avoiding the creation of remarkablyblurred luminous points, regardless of wavefront shape of an incidentlight beam.

[0012] Another object of the present invention is to provide a lensmeter and a reflecting telescope using the wavefront sensor.

[0013] To achieve the foregoing objects, the present invention providesin one aspect a wavefront sensor comprising: a plurality of lensesdisposed in the same plane; and an area sensor which receives a bundleof rays of light collected though each of the lenses as a luminous pointso that the wavefront sensor measures wavefront shape of a light beamincident to the lenses based on the position of the luminous points onthe area sensor. Each of the lenses comprises a plurality of concentricareas with different focal lengths, and the area sensor is locatedsubstantially halfway between a first position in which a plane waveforms an image after passing through one of the concentric areas with aminimum focal length, and a second position in which the plane waveforms an image after passing through another area with a maximum focallength.

[0014] In one preferred form of the invention, the respective focallengths of the concentric areas change stepwise from a central portiontoward a peripheral portion of each of the lenses. As an alternative,the respective focal lengths of the concentric areas change continuouslyfrom the central portion toward the peripheral portion of each of thelenses.

[0015] Form the manufacturing point of view, it is preferable that thecentral portion of each lens has the maximum focal length, and theperipheral portion of each lens has the minimum focal length.

[0016] The lenses preferably comprise a diffraction optical element.

[0017] In another aspect the present invention provides a lens meter inwhich the wavefront sensor of the foregoing construction isincorporated.

[0018] In still another aspect the present invention provides an activeoptical reflection telescope using the wavefront sensor of the foregoingconstruction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a schematic perspective view showing the generalconstruction of a wavefront sensor according to the present invention;

[0020]FIG. 2 is a plan view of a lens adapted to be mounted on thewavefront sensor;

[0021]FIG. 3 is an enlarged view showing the cross-sectional profile ofa diffraction optical element forming the lens;

[0022]FIG. 4 is a diagrammatical view showing an arrangement used whenthe wavefront sensor of the present invention is applied to a lensmeter;

[0023]FIG. 5 is a diagrammatical view showing the general constructionof a lens meter in which the wavefront sensor of the present inventionis incorporated;

[0024]FIG. 6(a) is a view illustrative of the manner in which an imageis formed when a convergent light beam is incident on the wavefrontsensor;

[0025]FIG. 6(b) is a view illustrative of the manner in which an imageis formed when a parallel light beam is incident on the wavefrontsensor;

[0026]FIG. 6(c) is a view illustrative of the manner in which an imageis formed when a divergent light beam is incident on the wavefrontsensor;

[0027]FIG. 7(a) is an enlarged view of a portion of FIG. 6(a) includingan area sensor; FIG. 7(b) is an enlarged view of a portion of FIG. 6(b)including the area sensor;

[0028]FIG. 7(c) is an enlarged view of a portion of FIG. 6(c) includingthe area sensor;

[0029]FIG. 8 is a graph showing a luminous energy distribution on thearea sensor of the wavefront sensor shown in FIGS. 6(a)-6(c);

[0030]FIG. 9 is a graph showing the manner in which the focal length ofthe lens continuously changes;

[0031]FIG. 10 is a fragmentary plan view of a lens array composed of aplurality of lens formed integrally in the same plane;

[0032]FIG. 11 is a diagrammatical view so the general construction of anactive optical reflecting telescope in which the wavefront sensor of thepresent invention is incorporated;

[0033]FIG. 12(a) is a view illustrative of the manner in which an imageis formed when a parallel light beam is incident on a conventionalwavefront sensor;

[0034]FIG. 12(b) is a view illustrative of the manner in which an imageis formed when a convergence light beam is incident on the conventionalwavefront sensor;

[0035]FIG. 12(c) is a view illustrative of the manner in which an imageis formed when a divergent light beam is incident on the conventionalwavefront sensor; and

[0036]FIG. 13 is a graph showing luminous energy distributions on anarea sensor of the wavefront sensor shown in FIGS. 12(a)-12(c).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The following description is merely exemplary in nature and is inno way intended to limit the invention or its application or uses.

[0038] Referring to the drawing and FIG. 1 in particular, there is shownthe general construction of a Hartmann wavefront sensor according to anembodiment of the present invention. The wavefront sensor 4 generallycomprises a Hartmann plate 6 having a plurality of openings 5 formedregularly therein at a constant interval, and an area sensor 7 disposedparallel to the Hartmann plate 6. An incident light beam P falls on orstrikes the Hartmann plate 6 from the opposite side of area sensor 7.The incident light beam P forms a thin pencil or bundle of rays of lightas it passes through the openings 5 and creates multiple luminous pointson the area sensor 7 corresponding in number to the number of theopenings 5.

[0039] Each of the openings 5 of the Hartmann plate 6 is equipped withone lens 8. The lens 8 has a focal length so set as to vary depending onportions thereof. In the illustrated embodiment, the lens 8, as shown inFIG. 2, has three concentric annular areas 8 a, 8 b and 8 c withdifferent focal lengths, and the focal lengths become smaller in agradual or otherwise stepwise fashion in a direction from a centralportion (area 8 a) of the lens 8 to a peripheral portion (area 8 c).From the manufacturing point of view, it is preferable that the lens 8comprises a diffraction optical element such as shown in FIG. 3.

[0040] The area sensor 7 is located substantially halfway between afirst position in which a plane wave forms an image when passing throughthe area 8 c having the minimum focal length f3, and a second positionin which the plane wave forms an image when passing through the area 8 ahaving the maximum focal length f1. Assuming that the distance from theHartmann plate 6 to the area sensor 7 is L, then, f3<<L<f1.

[0041] Application of Wavefront Sensor to Lens Meter

[0042]FIG. 4 schematically illustrates an arrangement taken when thewavefront sensor 4 of FIG. 1 is to be incorporated in a lens meter. InFIG. 4, these parts of a wavefront sensor 9 which are like orcorresponding to those of the wavefront sensor 4 are designated by thesame reference characters, and a further description thereof can,therefore, be omitted. FIG. 5 diagrammatically shows the generalconstruction of the lens meter 10 in which the wavefront sensor 9 isincorporated.

[0043] In the wavefront sensor 9, the center of a Hartmann plate 6 andthe center of an area sensor 7 are aligned with an optical axis of thelens meter 10. The Hartmann plate 6 has our openings 5 formed therein atequal angular intervals (with 90°pitch difference) about the center(optical axis). It is preferable that the number of the openings 5 isfour or more as in the illustrated embodiment when considering themeasurement accuracy. However, three openings can be enough when lenscharacteristics to be measured are the spherical focal power,cylindrical focal power, cylinder axis angle, or eccentricity.

[0044] The lens meter 10 comprises a light source 11, a pinhole 12, acollimator lens 13, a lens holder 14, and the wavefront sensor 9. Thepinhole 12 is located at a target focal point of the collimator lens 13.The lens holder 14 is adapted to support thereon a lens TL to be tested(hereinafter referred to as “tested lens”). WF in FIG. 5 denotes awavefront of the light beam P.

[0045] Light emitted from the light source 11 passes through the pinhole12, which forms a point light source. A light beam from the point lightsource then passes through the collimator lens 13, which creates a planewave (collimated light). When a lens TL to be tested is not placed onthe lens holder 14, the plane wave directly strikes the lenses 8 andthen is received by the area sensor 7. In this instance, the interval ofthe luminous points created on the area sensor 7 is equal to theinterval of the openings 5 in the Hartmann plate 6.

[0046] In the case where a lens TL to be test is placed on the lensholder 14, the plane wave incident to the lens TL is converted into aspherical wave according to the characteristics of the lens TL, thenpasses through the openings 5 in the Hartmann plate 6. When the testedlens TL is a plus lens or a lens having a positive focal power, theinterval of the luminous points created on the area sensor 7 becomessmaller than the interval of the openings in the Hartmann plate 6.Conversely, when the tested lens TL is a minus lens or a lens having anegative focal power, the interval of the luminous points on the areasensor 7 becomes greater than the interval of the openings in theHartmann plate 6. Accordingly, by obtaining the interval of the luminouspoints on the area sensor 7, the optical characteristics of a lens TL tobe tested, which is inserted on the light path, can be calculated. Forinstance, assuming that the distance between the apex on the backside ofthe tested lens TL and the Hartmann plate 6 is ΔL, the interval of theopenings 5 in the Hartmann plate 6 is d, and the displacement ofluminous points on the area sensor 7 relative to the luminous pointsformed in the absence of the tested lens TL is Δd, then a back focus Bfof the tested lens TL should be calculated by the equation below:

Bf=ΔLp31 L·d/Δd

[0047] For comparative purposes, a more specific example of the presentinvention will be described below in conjunction with a comparativeexample.

COMPARATIVE EXAMPLE

[0048] In the comparative example, the conventional wavefront sensorshown in FIGS. 12(a)-12(c) is used in the lens meter 10 in place of thewavefront sensor 9. The Hartmann plate 1 and area sensor 3 of theconventional wavefront sensor are similar to the Hartmann plate 6 andarea sensor 7, respectively, of the wavefront sensor 9 but differtherefrom in that the lenses 2 used in the Hartmann plate 1 comprise asingle focus lens.

[0049] In the case where the refracting power of the tested lens TL isapproximately 0 D, because a wavefront similar to the plane wave isincident to the Hartmann plate 1, the pinhole 12 forming a point lightsource focuses the light on the area sensor 3 and forms a clear or sharpluminous point Q1 (FIG. 12(a)). In this instance, since the luminouspoint Q1 has high luminous energy (as indicated by the solid line shownin FIG. 13) and excels in S/N ratio, the position of luminous point Q1can be detected with high accuracy. In addition, any scars orcontamination on the surface of the tested lens TL does not affect themeasurement result significantly.

[0050] On the other hand, when the refraction power of the tested lensTL is large or high, the wavefront of light beam P incident to theHartmann plate 1 forms a spherical wave with a small curvature. When thetested lens TL has a high plus or positive focal power, an image isformed far ahead of the area sensor 3 (FIG. 12(b)), and when the testedlens TL has a high minus or negative in power, an image is createdfarther behind the area sensor 3 (FIG. 12(c)). Accordingly luminouspoints Q2 and Q3 formed on the area sensor 3 become significantlyblurred. These blurred luminous points Q2 and Q3 have lower peakluminous energy (indicated by the broken line shown in FIG. 13) and lowS/N ratio, thereby significantly deteriorating the accuracy of positiondetection of luminous points Q2 and Q3. In addition, a scar orcontamination on the surface of the tested lens TL tends to produceerrors in the measurement result.

[0051] It is possible to obtain less blurred luminous points by makingthe openings in Hartmann plate 1 smaller to thereby deepen the depth offocus. This measure is, however, practically undesirable as it decreasesthe luminous energy on the area sensor 3. It is also possible to move ordisplace the area sensor 3 according to the focal power of tested lensTL in such a manner as to keep the focal point always located on thearea sensor 3. However, this requires an additional area-sensor movingmechanism, causes enlargement of the lens meter as a whole due to thecomplexity of optical system, incurs an additional cost, and causeselongation of the measurement time.

INVENTIVE EXAMPLE

[0052] In the inventive example, the respective focal lengths f1, f2 andf3 of the concentric areas 8 a, 8 b and 8 c of the wavefront sensor 9arm set such that an image can be formed on the area sensor 7 when eachof tested lenses TL with focal powers +10 D, 0 D, and −10 D is placed onthe lens meter 10. For example, when ΔL=5 mm and L=15 mm, the focallengths f1, f2, and f3 should be +17.8, +15, and +13.1 mm, respectively.

[0053] When a spherical wave generated by the +10 D tested lens TL isincident to the lens 8, light P1 passing though the area 8 a forms animage on the area sensor 7, as shown in FIG. 6(a) and FIG. 7(a). At thistime, light P2 passing through the area 8 b forms an image at a pointahead of the area sensor 7, and light P3 passing through the area 8 cforms an image at a point farther ahead of the area sensor 7.

[0054] When a plane wave generated by the 0 D tested lens TL is incidentto the lens 8, light P2 passing though the area 8 b forms an image onthe area sensor 7, as shown in FIG. 6(b) and FIG. 7(b). In thisinstance, light P2 passing through the area 8 a forms an image behindthe area sensor 7 (actually, an image does not created because the areasensor 7 blocks the light), and light P3 passing through the area 8 cforms an image ahead of the area sensor 7.

[0055] When a spherical wave generated by the −10 D tested lens TL isincident to the lens 8, light beam P3 passing though the area 8 c formsan image on the area sensor 7, as shown in FIG. 6(c) and FIG. 7(c). Inthis instance, light P2 passing through the area 8 b forms an imagebehind the area sensor 7, and light P1 passing through the area 8 aforms an image still farther behind the area sensor 7.

[0056] In FIGS. 7(a)-7(c), R1, R2, and R3 denote image-forming points ofthe lights P1, P2 and P3, respectively.

[0057] In the inventive example, part of the light beam P forms an imageon or in the vicinity of the area sensor 7 regardless of wavefront shapeof the incident light beam P, by passing through any of the areas 8 a, 8b and 8 c in the lens 8. Thus, the luminous energy distribution such asshown in FIG. 8 can be obtained even when the remainder of light beam Pincident to an unmatched area, such as the area 8 a or 8 b for the planewave. The luminous energy distribution thus obtained has a low peakvalue and obtains a blurred luminous point, when compared with theluminous energy distribution (indicated by the solid line shown in FIG.13) obtained around 0 D, which is properly focused. However, thisblurred image does not significantly affect the accuracy of detection ofluminous points by the area sensor 7. On the contrary, when comparedwith the luminous energy distribution (indicated by the broken lineshown in FIG. 13) obtained by the tested lens TL with a higherrefracting power, which cannot obtain proper focus, the luminous energydistribution of the inventive example has a higher peak value andobtains a luminous point with a smaller diameter, leading to an improveddegree of measurement accuracy.

[0058] The wavefront sensor according to the comparative example isdifficult to maintain constant measurement accuracy because it createsgreat differences in luminous energy and diameter depending on wavefrontshape of the incident light beam P. However, the wavefront sensor 9 ofthe inventive example can always maintain constant luminous energy anddiameter of the luminous points regardless of wavefront shape of theincident light beam P, thus securing a highly accurate measurement.

[0059] Although in the inventive example, the focal lengths f1, f2 andf3 of the lens 8 changes gradually or otherwise stepwise, the lens mayhave a focal length varying continuously in a direction from the centralportion of the lens toward the peripheral portion, as indicated by aspherical aberration curve shown in FIG. 9. For example, assuming thatwhen transmitted light from a +25 tested lens passes through a centralportion of the lens 8 including the optical axis, an image is formed onthe area sensor 7, and when transmitted light from a −25 D tested lensTL passes through an outermost peripheral portion of the lens 8, animage is formed on the area sensor 7, then the focal length of thecentral portion should be set to 26.3 mm, and that of the outermostperipheral portion to 11.3 mm (spherical aberration of the outermostperipheral portion is −15 mm), and the focal length of an intermediateportion between the central and outermost peripheral portions should beset to vary continuously from 26.3 mm to 11.3 mm.

[0060] The focal length of the lens 8 thus becoming smaller eithergradually or continuously from the central portion of the lens 8 towardthe peripheral portion is for the convenient of manufacture of thelenses. The arrangement should by no means be limited to this, but mayinclude a lens with a focal length varying gradually from the peripheralportion toward the central portion. Further, the focal length varyingcontinuously or gradually in the radial direction of the lens is not anessential requirement for the invention.

[0061] Because aspherical lenses are difficult to manufacture only byway of grinding, it is desirable to produce the lenses as a diffractionoptical element previously described. In addition, the lenses may alsobe formed integrally as a single binary lens array.

[0062] Application of the Wavefront Sensor to Reflecting Telescope

[0063]FIG. 11 diametrically shows the general construction of an activeoptical reflecting telescope in which the wavefront sensor of thepresent invention is incorporated. In the reflecting telescope 15, alight beam P from a distant point is reflected by a concave mirror 16toward a convex mirror 17. The light beam reflected by the convex mirror17 passes through an opening 18 formed in a central portion of theconcave mirror 16, and then passes through a beam splitter 19 to reachan observation plane 20. The beam splitter 19 reflects part of the lightbeam and, the reflected part of light beam, as it subsequently passesthrough a collimator lens 21, becomes parallel rays of light. Theparallel rays are then introduced into a wavefront sensor 22 comprisedof a Hartmann plate 6 equipped with lenses 8 (cf. FIG. 1) and an areasensor 7.

[0064] A plurality of actuators 23 is disposed on the back of theconcave mirror 16 for deforming the surface of the mirror 16. Theactuators 23 are driven to deform the mirror surface so that a distortedwavefront WF is converted into a well-formed spherical wavefront WF. Inthis instance, it is necessary to obtain the amount of distortion of theincident wavefront WF and the amount of deformation of the mirrorsurface due for the compensation of the wavefront distortion, and todetermine the amount of movement of the actuators 23 based on thedesired deformation of the mirror surface. The wavefront sensor 22 isused to detect the wavefront distortion. An arithmetic circuit 24 isconnected to the wavefront sensor 22 for determining, on the basis ofthe detected wavefront distortion, a necessary amount of movement of theactuators 23. The actuators 23 are driven based on the movement amountdetermined by the arithmetic circuit 24.

[0065] As described above, since according to the present invention,light passing through any of plural concentric areas of different focallengths in each lens creates an image on or in the vicinity of an areasensor, the measurement can be always achieved with high accuracywithout involving remarkable blurring of luminous points regardless ofthe shape of wavefront.

[0066] Obviously, various minor changes and modifications of the presentinvention are possible in the light of the above teaching. It istherefore to be understood that within the scope of the appended claims,the present invention may be practiced otherwise than as specificallydescribed.

What is claimed is:
 1. A wavefront sensor comprising: a plurality of lenses disposed in the same plane; and an area sensor which receives a bundle of rays of light collected through each of said lenses as a luminous point, wherein the wavefront sensor measures wavefront shape of a light beam incident to said lenses based on the position of the luminous points on said area sensor, characterized by—each of said lenses comprises a plurality of concentric areas with different focal lengths, and said area sensor is located substantially halfway between a first position in which a plane wave forms an image after passing through one of said concentric areas with a minimum focal length, and a second position in which the plane wave forms an image after passing through another area with a maximum focal length.
 2. The wavefront sensor according to claim 1 , wherein the respective focal lengths of said plurality of concentric areas change stepwise from a central portion toward a peripheral portion of each of said lenses.
 3. The wavefront sensor according to claim 1 , wherein the respective focal lengths of said concentric areas change continuously from a central portion toward a peripheral portion of each of said lenses.
 4. The wavefront sensor according to claim 2 , wherein the central portion of each of said lenses has the maximum focal length, and the peripheral portion of each of said lenses has the minimum focal length.
 5. The wavefront sensor awarding to claim 3 , wherein the central portion of each of said lenses has the maximum focal length, and the peripheral portion of each of said lenses has the minimum focal length.
 6. The wavefront sensor according to claim 1 , wherein said lenses each comprise a diffraction optical element.
 7. The wavefront sensor according to claim 2 , wherein said lenses each comprise a diffraction optical element.
 8. The wavefront sensor according to claim 3 , wherein said lenses each comprise a diffraction optical element.
 9. The wavefront sensor according to claim 4 , wherein said lenses each comprise a diffraction optical element.
 10. The wavefront sensor according to claim 5 , wherein said lenses each comprise a diffraction optical element.
 11. A lens meter using the wavefront sensor according to claim 1 .
 12. A lens meter using the wavefront sensor according to claim 2 .
 13. A lens meter using the wavefront sensor according to claim 3 .
 14. A lens meter using the wavefront sensor according to claim 4 .
 15. A lens meter using the wavefront sensor according to claim 5 .
 16. A lens meter using the wavefront sensor according to claim 6 .
 17. A lens meter using the wavefront sensor according to claim 7 .
 18. A lens meter using the wavefront sensor according to claim 8 .
 19. A lens meter using the wavefront sensor according to claim 9 .
 20. A lens meter using the wavefront sensor according to claim 10 .
 21. An active optical reflection telescope using the wavefront sensor according to claim 1 .
 22. An active optical reflection telescope using the wavefront sensor according to claim 2 .
 23. An active optical reflection telescope using the wavefront sensor according to claim 3 .
 24. An active optical refection telescope using the wavefront sensor according to claim 4 .
 25. An active optical reflection telescope using the wavefront sensor according to claim 5 .
 26. An active optical reflection telescope using the wavefront sensor according to claim 6 .
 27. An active optical reflection telescope using the wavefront sensor according to claim 7 .
 28. An active optical reflection telescope using the wavefront sensor according to claim 8 .
 29. An active optical reflection telescope using the wavefront sensor according to claim 9 .
 30. An active optical reflection telescope using the wavefront sensor according to claim 10 . 